. Natural history. Zoology. NEWTS AND SALAMANDERS. 449 Islands, constitute a genus confined to the Oriental region, and differing from all those mentioned above in the conformation of the skull in which the pterygoid bones extend forwards to touch the maxillie, instead of being separated from them by an interval. These salamanders have five hind-toes and tlie tail strongly compressed. They are inhabitants of mountain dis- tricts. Nearly al led is the single species of PachytHton, from South Kiansi China, m which the tail is cyUndrical at the root, although compressed near the tip. o i In the s
. Natural history. Zoology. NEWTS AND SALAMANDERS. 449 Islands, constitute a genus confined to the Oriental region, and differing from all those mentioned above in the conformation of the skull in which the pterygoid bones extend forwards to touch the maxillie, instead of being separated from them by an interval. These salamanders have five hind-toes and tlie tail strongly compressed. They are inhabitants of mountain dis- tricts. Nearly al led is the single species of PachytHton, from South Kiansi China, m which the tail is cyUndrical at the root, although compressed near the tip. o i In the second sub-family — ^mfeZysfomaimfe — of the Salamandridce the teeth on the palate form either a transverse or posteriorly converging series, and are attached to the hinder margin of the posterior portion" of the vomers, instead of to processes of the palatine bones. The vertebrse, too, differ from those of the first group in that both terminal faces of their bodies are sHghtly cupped; this being a lower type of structure than the ball-and- socket articulation. The type of this group is the creature known in Mexico as the axolotl, which is the permanent larval form of a salamander from the United States described as AvMystoma tirjrhium. It was long thout^ht that these two forms were totally distinct animals ; but the identity of the two was conclusively proved by some Mexican axolotls kept many years ago in Paris. One of these layed eggs, which in due course developed into axolotls, but these latter ulti- mately assumed the form of the adult salamander. The most curious fact about the matter was that where- as the axolotls bred freely, none of the adult salamanders could be in- duced to propagate their kind. There are several species of the genus in- habiting North America, and a suigle • outlying form in the mountains of pig^ Axolotl Siam. With the single exception of (AmUijstomatigrmum). the Mexican race of Ainblystcmia tigrinum, all these appear to pass f
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